On Thu, Aug 01, 2013 at 05:51:31PM -0700, Linus Torvalds wrote:

This one may have been going on for some time - I haven't updated the old Intel Mac Mini in a while.

And by "not updated" I also mean that it's some really old user-space: the machine is running F14, and cannot be updated to anything newer without having to reinstall everything because of a stupid small /boot partition. So it's not going to happen. But maybe somebody cares about the i915 warning anyway?

            Linus

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WARNING: CPU: 1 PID: 2846 at drivers/gpu/drm/i915/intel_sdvo.c:1378 intel_sdvo_get_config+0x158/0x160() SDVO pixel multiplier mismatch, port: 0, encoder: 1 Modules linked in: snd_hda_codec_idt snd_hda_intel snd_hda_codec snd_hwdep CPU: 1 PID: 2846 Comm: Xorg Not tainted 3.11.0-rc3-00208-gbe1e8d7-dirty #19 Hardware name: Apple Computer, Inc. Macmini1,1/Mac-F4208EC8, BIOS MM11.88Z.0055.B03.0604071521 04/07/06 00000000 00000000 ef0afa54 c1597bbb c1737ea4 ef0afa84 c10392ca c1737e6c ef0afab0 00000b1e c1737ea4 00000562 c12dfbe8 c12dfbe8 ef0afb14 00000000 f697ec00 ef0afa9c c103936e 00000009 ef0afa94 c1737e6c ef0afab0 ef0afadc Call Trace: [<c1597bbb>] dump_stack+0x41/0x56 [<c10392ca>] warn_slowpath_common+0x7a/0xa0 [<c103936e>] warn_slowpath_fmt+0x2e/0x30 [<c12dfbe8>] intel_sdvo_get_config+0x158/0x160 [<c12c3220>] check_crtc_state+0x1e0/0xb10 [<c12cdc7d>] intel_modeset_check_state+0x29d/0x7c0 [<c12dfe5c>] intel_sdvo_dpms+0x5c/0xa0 [<c12985de>] drm_mode_obj_set_property_ioctl+0x40e/0x420 [<c1298625>] drm_mode_connector_property_set_ioctl+0x35/0x40 [<c1289294>] drm_ioctl+0x3e4/0x540 [<c10fc1a2>] do_vfs_ioctl+0x72/0x570 [<c10fc72f>] SyS_ioctl+0x8f/0xa0 [<c159b7fa>] sysenter_do_call+0x12/0x22 ---[ end trace 7ce940aff1366d60 ]---

Looks like this could happen when you go to DPMS_OFF. After we've turned off the the pipe, get_pipe_config() gives a mostly zeroed pipe_config (including pixel_multiplier), and then in the case of SDVO, we go and check it against the encoder's idea of pixel_multiplier anyway.

I'm thinking perhaps we shouldn't call get_config for inactive encoders. How about the following patch?

From 16c4048bfb54e338ce23a7e98af96af2f58b0e0d Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= ville.syrjala@linux.intel.com Date: Fri, 2 Aug 2013 12:06:47 +0300 Subject: [PATCH] drm/i915: Don't call encoder's get_config unless encoder is active

--- drivers/gpu/drm/i915/intel_display.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index e1e50df..6396bca 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8549,9 +8549,11 @@ check_crtc_state(struct drm_device *dev)

list_for_each_entry(encoder, &dev->mode_config.encoder_list, base.head) { + enum pipe pipe; if (encoder->base.crtc != &crtc->base) continue; - if (encoder->get_config) + if (encoder->get_config && + encoder->get_hw_state(encoder, &pipe)) encoder->get_config(encoder, &pipe_config); }